Heavy Rain in Arizona, August 2, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
910 PM MST SAT AUG 02 2014

.SYNOPSIS...DEEP MONSOON MOISTURE AND A LOW PRESSURE SYSTEM MOVING
INTO SOUTHERN CALIFORNIA WILL PRODUCE AN EXTENDED PERIOD OF SHOWERS
AND THUNDERSTORMS THROUGH SUNDAY. THESE STORMS WILL BE CAPABLE OF
PRODUCING LOCALLY HEAVY RAINFALL...ELEVATING THE RISK OF FLASH
FLOODING ACROSS ARIZONA. BEGINNING MONDAY...EXPECT THUNDERSTORM
ACTIVITY TO TREND DOWNWARD...WITH WARMING TEMPERATURES.

&&

.DISCUSSION...A SOMEWHAT UNUSUAL UPPER LOW FOR THIS TIME OF YEAR IS
APPROACHING SAN DIEGO THIS EVENING. DYNAMICS TO THE NORTH AND EAST
OF THE LOW ARE NOW INTERACTING WITH A PLUME OF TROPICAL MOISTURE
OVER ARIZONA AND SOUTHERN CALIFORNIA. WITH MOST CAPE HAVING BEEN
USED UP EARLIER TODAY...THIS IS NOW RESULTING IN AN EXPANDING AREA
OF LIGHT TO MODERATE RAINFALL...WITH EMBEDDED SHALLOW CONVECTION.
IT IS HARD TO TELL IF OUR CURRENT FLASH FLOOD WATCH IS GOING TO PAN
OUT...BUT SUCH A LARGE AREA OF RAINFALL WILL SATURATE THE GROUND
TONIGHT AND ANY EMBEDDED MODERATE TO HEAVY RAIN COULD PROMPT
FLOODING INTO SUNDAY. THEREFORE...THE WATCH WILL REMAIN AND MAY EVEN
BE EXTENDED THROUGH SUNDAY AFTERNOON...AS THE COLD POOL APPROACHES
OUR WESTERN AND CENTRAL ZONES.

AFTER SUNDAY...DRIER SOUTHWESTERLY FLOW DEVELOPS WITH WARMING
TEMPERATURES ALOFT. THIS WILL MAKE FOR A DOWNTREND IN CONVECTION
NEXT WEEK...WITH A WARMING TREND WITH DAYTIME TEMPERATURES.
ZONES/GRIDS LOOK GOOD AND NO SIGNIFICANT UPDATES ARE NEEDED.

&&

.AVIATION...FOR THE 06Z PACKAGE...EXPECT WDSPRD -SHRA/SHRA WITH
EMBEDDED ISOLD -TSRA ALONG AND SOUTH OF A LINE FROM KGCN TO KRQE
THROUGH MUCH OF THE PERIOD. CIGS WILL RANGE FROM 4-8KFT AGL WITH SCT
MVFR CONDITIONS IN RAIN AND MIST. THE NE CORNER OF AZ WILL SEE ONLY
ISOLD TO SCT ACTIVITY IN -SHRA/-TSRA. SOME IMPROVEMENT IN THE
STRATIFORM ENVIRONMENT LIKELY AFTER 20Z-22Z SUNDAY...ALTHOUGH THIS
COULD LEAD TO ISOLD +TSRA DURING THE AFTERNOON. AVIATION DISCUSSION
NOT UPDATED FOR AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

FLASH FLOOD WATCH UNTIL 6 AM MST SUNDAY FOR AZ PUBLIC ZONES
004>009-012>018-037-038-040.

&&

PUBLIC.........PETERSON
AVIATION.......PETERSON

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
504 AM MST SAT AUG 2 2014

AZZ004>018-037>040-030700-
KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRY-
COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINS-
NORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEY-
CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
WESTERN MOGOLLON RIM-EASTERN MOGOLLON RIM-WHITE MOUNTAINS-
NORTHERN GILA COUNTY-YAVAPAI COUNTY VALLEYS AND BASINS-
OAK CREEK AND SYCAMORE CANYONS-BLACK MESA AREA-
NORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-
504 AM MST SAT AUG 2 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR APACHE...COCONINO...
NORTHERN GILA...NAVAJO...AND YAVAPAI COUNTIES IN NORTHERN
ARIZONA.

.DAY ONE...TODAY AND TONIGHT

A SEASONABLY STRONG UPPER LEVEL TROUGH WILL PRODUCE NUMEROUS HEAVY
SHOWERS AND THUNDERSTORMS ACROSS ARIZONA THIS AFTERNOON AND
OVERNIGHT. SLOW MOVING HEAVY SHOWERS MAY FILL UP AREA WASHES AND
STREAMS...SIGNIFICANTLY INCREASING THE THREAT FOR FLASH FLOODING. A
FLASH FLOOD WATCH HAS BEEN ISSUED FROM NOON TODAY THROUGH EARLY
SUNDAY MORNING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SHOWERS AND THUNDERSTORMS WILL GRADUALLY DECREASE ACROSS CENTRAL
ARIZONA ON SUNDAY. DRIER SOUTHWESTERLY FLOW IS FORECAST THROUGH
THE FIRST HALF OF NEXT WEEK WITH A DOWNWARD TREND IN SHOWERS AND
THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.